Optical apparatuses such as digital still cameras and video cameras generally have a zoom lens mounted therein and a multiplicity of suitable zoom lenses have been proposed. Nowadays, portability has become extremely important for optical apparatuses such as digital still cameras and steps toward miniaturizing zoom lenses which are photographic lenses and making zoom lenses lightweight have been taken in order to miniaturize the camera main body and render same thin and lightweight. Among such zoom lenses, a zoom lens in which a portion of the lens system comprises an optical element that is capable of bending the path of light through approximately 90 degrees has been proposed. By installing a zoom lens of this kind, where the transition is made from a housed state to a usage state, there is no protrusion from the camera main body, which affords superior portability in the usage state and also makes a large contribution toward creating a thinner and more miniature camera.
However, a large number of zoom lenses that comprise an optical element that makes it possible to bend the path of light through approximately 90 degrees excel with respect to miniaturization and the production of a thinner camera and, therefore, the focal length in the wide-angle end state is large and an enlargement of the field of view is ignored. Hence, users have been able to photograph over a wider range and obtain results of a perspective that is closer to the object. Conventional zoom lenses that are capable of bending the path of light include a five-group type zoom lens comprising, in order from the object, a first lens group which has positive refractive power, a second lens group which has negative refractive power, a third lens group which has positive refractive power, a fourth lens group which has positive refractive power, and a fifth lens group which has negative refractive power. (See Japanese Application Laid Open No. 2005-84283, for example).
In addition, while a camera of this kind is more miniature, thinner, and more lightweight, it is, on the other hand, difficult to hold such a camera in the usage state and there has been the risk of considerable photographic failure due to camera shake and so forth. More specifically, there has been the risk of degradation of the image quality due to image shaking during exposure as a result of the minute amount of camera shake that occurs during photography (camera shake that occurs where the photographer pushes the release button). Therefore, a method of correcting image shake by driving a shift lens group to compensate for image shake that occurs in such camera shake by combining, as an optical system which is capable of image-shifting the zoom lens, a detection system for detecting camera shake, a calculation system that controls the shift lens group in accordance with a value output by the detection system, and a drive system that shifts the shift lens group, is known.
As a zoom lens that is capable of image-shifting, Japanese Application Laid Open No. 2000-298235, for example, is known. Japanese Application Laid Open No. 2000-298235 discloses a zoom lens which comprises a first lens group which has positive refractive power, a second lens group which has negative refractive power, a third lens group which has positive refractive power, a fourth lens group which has negative refractive power, and a fifth lens group which has positive refractive power, wherein the whole of the third lens group is moved in a direction which is substantially vertical to the optical axis to correct shaking of the photographic image where the variable power optical system vibrates.